JP2008152019A - Light source device, image display apparatus, projector, illumination apparatus and monitor apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device which can produce illumination light capable of efficiently illuminating a prescribed surface. <P>SOLUTION: The light source device which produces the illumination light for illuminating the prescribed surface comprises: a plurality of laser beam sources for emitting laser beams; a diffractive optical element which diffracts incident light and emits light for being supplied to the prescribed surface; and an optical system which allows a plurality of laser beams emitted from the respective laser beam sources to be made incident, condenses the plurality of laser beams made incident and makes condensed light incident to the diffractive optical element. The optical system condenses at least a part of the plurality of laser beams to the center side of the prescribed surface and makes light incident to the diffractive optical element. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light source device, an image display device, a projector, an illumination device, and a monitor device.

A technique using a laser light source has been proposed in a projection-type image display device (projector) that projects color light including image information generated by a spatial light modulation device such as a liquid crystal device onto a screen using a projection system.
Japanese Patent Laid-Open No. 11-64789 JP 2000-162548 A

  In a projector, it is important to efficiently illuminate the incident surface of the spatial light modulator with laser light. Therefore, it is important to construct an optical system for efficiently illuminating the incident surface of the spatial light modulator with laser light.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a light source device capable of generating irradiation light capable of efficiently illuminating a predetermined surface. It is another object of the present invention to provide an image display device and a projector that display an image using light emitted from a light source device. It is another object of the present invention to provide an illumination device and a monitor device that use light emitted from a light source device.

  In order to solve the above problems, the present invention adopts the following configuration.

  According to a first aspect of the present invention, there is provided a light source device that generates irradiation light for irradiating a predetermined surface, a plurality of laser light sources that emit laser light, and diffracting incident light to be incident on the predetermined surface. A diffractive optical element that emits light to be supplied and a plurality of laser beams emitted from each of the laser light sources are incident, the plurality of incident laser beams are condensed, and the collected light And an optical system that makes the light incident on the diffractive optical element, the optical system condensing at least a part of the plurality of laser beams on the center side of the predetermined surface and making the light incident on the diffractive optical element A light source device is provided.

  According to the first aspect of the present invention, by providing a plurality of laser light sources, it is possible to generate irradiation light having high illuminance (luminance) for illuminating a predetermined surface, and suppress generation of speckle patterns, The predetermined surface can be well illuminated. In addition, an optical system for condensing a plurality of laser beams emitted from each of the plurality of laser light sources is provided, and the light condensed by the optical system is made incident on the diffractive optical element. Irradiation light that can be illuminated can be generated. Then, by condensing a plurality of laser beams on the center side of the predetermined surface, high diffraction efficiency can be realized, and a light source device with high light utilization efficiency can be realized.

  In the light source device of the present invention, the optical system may employ a configuration in which the plurality of laser beams incident on the diffractive optical element are made parallel. Thereby, the wavefront of the light incident on the diffractive optical element can be made flat, and the diffractive optical element can generate desired diffracted light satisfactorily with high diffraction efficiency. In addition, by flattening the wavefront of light incident on the diffractive optical element, it is possible to reduce the burden when designing the diffractive optical element and when manufacturing the light source device.

  In the light source device of the present invention, the diffractive optical element has an incident part and an emission part, diffracts the light incident on the incident part by the emission part, is arranged at the incident part, and is supplied to the emission part It is possible to adopt a configuration having a collimating optical element that collimates the plurality of laser beams. Thereby, desired diffracted light can be generated satisfactorily with high diffraction efficiency while suppressing an increase in the number of parts.

  In the light source device of the present invention, the optical system may employ a configuration in which the optical axis of the optical system is arranged so as not to intersect a predetermined region of the predetermined surface. Thereby, it can suppress that the light inject | emitted from the optical system is directly supplied to a predetermined surface.

  In the light source device of the present invention, the diffractive optical element can employ a configuration in which 0th-order light generated from the diffractive optical element is arranged so as not to enter a predetermined region of the predetermined surface. As a result, even if zero-order light is generated from the diffractive optical element, the zero-order light can be prevented from entering the predetermined surface. Therefore, the predetermined surface can be illuminated in a desired state.

  In the light source device of the present invention, the optical system can employ a configuration including a refractive lens. As a result, it is possible to reduce the manufacturing burden in designing the optical system.

  In the light source device of the present invention, the optical system can employ a configuration including a Fresnel lens. Thereby, an optical system can be reduced in size.

  In the light source device of the present invention, the diffractive optical element has a plurality of cell regions that receive light from the optical system and emit light for supplying the predetermined surface with predetermined diffraction efficiency, A configuration in which the diffraction efficiencies of the cell regions are approximately equal can be employed. Thereby, the predetermined surface can be efficiently illuminated with high illuminance by light generated from each cell region having high diffraction efficiency. Further, it is possible to suppress the generation of speckle patterns and illuminate a predetermined surface with a substantially uniform illuminance distribution.

  In the light source device of the present invention, the diffractive optical element has a plurality of cell regions that receive light from the optical system and emit light for supplying the predetermined surface with predetermined diffraction efficiency, A plurality of irradiation regions formed by light supplied to the predetermined surface from each of the cell regions can adopt a configuration that matches the predetermined surface. Thereby, the predetermined area | region of a predetermined surface can be illuminated in a superimposed manner with the light generated from each cell area. Thereby, a predetermined surface can be efficiently illuminated with high illuminance. Further, it is possible to suppress the generation of speckle patterns and illuminate a predetermined surface with a substantially uniform illuminance distribution.

  According to a second aspect of the present invention, there is provided an image display device characterized in that the irradiation light from the light source device described above is irradiated and an image is displayed by the light through the predetermined surface.

  According to the second aspect of the present invention, a desired image can be obtained by irradiation light through a predetermined surface illuminated in a desired state.

  In the image display device of the present invention, the predetermined surface may include a light incident surface of a spatial light modulator that modulates the irradiated light according to an image signal. Thereby, a desired image can be displayed.

  According to a third aspect of the present invention, there is provided a projector including the image display device described above, and including a projection system that projects light including image information via the predetermined surface onto the display surface. Is done.

  According to the third aspect of the present invention, a good image can be formed.

  According to the 4th viewpoint of this invention, the illuminating device provided with the light source device as described above is provided.

  According to the fourth aspect of the present invention, it is possible to illuminate a predetermined surface with a uniform illuminance distribution with irradiation light with high illuminance.

  According to a fifth aspect of the present invention, there is provided a monitor device comprising the light source device described above.

  According to the fifth aspect of the present invention, an object can be illuminated with irradiation light with high illuminance, and the object can be monitored well.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, an XYZ orthogonal coordinate system is set, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. The predetermined direction in the horizontal plane is the X-axis direction, the direction orthogonal to the X-axis direction in the horizontal plane is the Y-axis direction, and the direction orthogonal to each of the X-axis direction and the Y-axis direction (that is, the vertical direction) is the Z-axis direction. To do. Further, the rotation (inclination) directions around the X axis, Y axis, and Z axis are the θX, θY, and θZ directions, respectively.

<First Embodiment>
A first embodiment will be described. FIG. 1 is a schematic configuration diagram showing a light source device 1 according to the first embodiment, and FIG. 2 is a perspective view schematically showing FIG. 1 and 2, a light source device 1 generates irradiation light for irradiating a predetermined surface 11 of a predetermined member 10, and includes a plurality of laser light sources 2 that emit laser light and incident laser light. Are diffracted and a plurality of laser beams emitted from each of a plurality of laser light sources 2 are incident and incident. And an optical system 8 for condensing the plurality of laser beams and making the collected light incident on the diffractive optical element 5. The optical system 8 condenses at least a part of the plurality of laser beams from the laser light source 2 on the center side (−X side in the drawing) of the predetermined surface 11 and makes the light enter the diffractive optical element 5. In the present embodiment, the predetermined surface 11 is substantially parallel to the XY plane. In the following description, a case where the light source device 1 irradiates a predetermined area (illumination area) of the predetermined surface 11 substantially parallel to the XY plane will be described as an example. The predetermined surface 11 of the predetermined member 10 and the illumination area have substantially the same size.

  The diffractive optical element 5 is disposed between the laser light source 2 and the predetermined surface 11. The optical system 8 is disposed between the laser light source 2 and the diffractive optical element 5. In this embodiment, an angle adjusting optical element 9 is disposed between the diffractive optical element 5 and the predetermined surface 11. In FIG. 2, the angle adjusting optical element 9 is not shown.

  The laser light source 2 emits laser light. In the present embodiment, a plurality of laser light sources 2 are provided, and the light emission surface of each laser light source 2 faces the + Z side. Each laser light source 2 emits laser light substantially parallel to the Z axis in the + Z direction. In the present embodiment, a plurality of laser light sources 2 are arranged in a two-dimensional direction (XY directions in the examples of FIGS. 1 and 2). Each of the plurality of laser light sources 2 irradiates the optical system 8 with laser light.

  The optical system 8 is irradiated with a plurality of laser beams emitted from each of the plurality of laser light sources 2, condenses the plurality of laser beams, and causes the collected laser beams to enter the diffractive optical element 5. .

  In the present embodiment, the optical system 8 includes a first optical element 6 having an incident surface 6A on which the laser light from the laser light source 2 is incident, and an emission surface 6B on which the laser light from the incident surface 6A is emitted. The second optical element 7 includes an incident surface 7A on which the laser light from the optical element 6 is incident and an emission surface 7B on which the laser light from the incident surface 7A is emitted.

  In the present embodiment, each of the first optical element 6 and the second optical element 7 is a refractive lens (geometric optical lens). The incident surface 6A of the first optical element 6 is a plane substantially parallel to the XY plane, and the exit surface 6B is a curved surface that is convex toward the + Z side (the side opposite to the laser light source 2). That is, the first optical element 6 of the present embodiment is a so-called plano-convex lens. The incident surface 7A of the second optical element 7 is a plane substantially parallel to the XY plane, and the exit surface 7B is a curved surface that is recessed toward the + Z side (the side opposite to the laser light source 2). That is, the second optical element 7 of the present embodiment is a so-called plano-concave lens.

  The optical system 8 including the first optical element 6 and the second optical element 7 condenses and emits a plurality of laser beams incident from the laser light source 2. The optical system 8 collimates a plurality of emitted laser beams (light beam groups). That is, the optical system 8 of the present embodiment has a function as a condensing optical system that condenses and emits incident light, and a collimating optical system (a collimating optical system, a collimating optical system that collimates the emitted light. ) As a function. In the present embodiment, in the optical system 8, the first optical element 6 mainly exhibits a condensing function, and the second optical element 7 mainly exhibits a collimating function (a collimating function, a collimating function). To do.

  The optical system 8 condenses, collimates (collimates) a plurality of laser beams (light beam groups) emitted from the laser light source 2 and incident on the diffractive optical element 5, condenses them, and collimates them (views). The normalized laser beam is incident on the diffractive optical element 5.

  The optical system 8 condenses at least a part of the laser light emitted from the laser light source 2 on the center side of the predetermined surface 11. In the present embodiment, the optical system 8 (and the diffractive optical element 5) is disposed so as to be shifted to the + X side with respect to the predetermined surface 11 of the predetermined member 10, and the optical system 8 is emitted from the laser light source 2. At least a part of the laser beam is condensed on the −X side.

  The diffractive optical element 5 has an incident surface 3 on which the laser light from the optical system 8 is incident and an emission surface 4 on which the laser light from the incident surface 3 is emitted, and diffracts the laser light incident on the incident surface 3. Laser light for generating diffracted light and supplying it to the predetermined surface 11 is emitted from the emission surface 4.

  The incident surface 3 of the diffractive optical element 5 is irradiated with collimated laser light from the optical system 8. In the present embodiment, the incident surface 3 of the diffractive optical element 5 is substantially parallel to the XY plane, and the optical system 8 emits laser light substantially parallel to the Z axis. That is, in the present embodiment, the laser light from the optical system 8 is incident on the incident surface 3 of the diffractive optical element 5 substantially perpendicularly. In the present embodiment, the exit surface 4 of the diffractive optical element 5 is also substantially parallel to the XY plane.

  The diffractive optical element 5 is made of a material that can transmit laser light, such as quartz (glass), transparent synthetic resin, or the like. The diffractive optical element 5 of this embodiment includes a computer generated hologram (CGH).

  The diffractive optical element (hologram element) 5 has an illumination area setting function, a diffused light generation function (illuminance uniformity function), and an enlarged illumination function. A light source device 1 including a diffractive optical element 5 having an illumination area setting function illuminates a predetermined surface 11 with a predetermined illumination area based on laser light emitted from a laser light source 2 and supplied via an optical system 8. . Further, the light source device 1 including the diffractive optical element 5 having a diffused light generation function equalizes the illuminance of at least a part of the illumination area of the predetermined surface 11. Further, the light source device 1 including the diffractive optical element 5 having an enlarged illumination function illuminates the predetermined surface 11 with an illumination area larger than an emission area where light is emitted from the emission surface 4 of the diffractive optical element 5.

  3A and 3B are schematic diagrams illustrating an example of a diffractive optical element, in which FIG. 3A is a plan view and FIG. 3B is a cross-sectional view taken along line AA in FIG. In FIG. 3, the diffractive optical element 5 has a plurality of rectangular recesses (uneven structure) 5M on its surface. The recesses 5M have different depths. The plurality of convex portions between the concave portions 5M also have different heights. Then, by appropriately adjusting the surface conditions of the diffractive optical element 5 including the pitch d between the concave parts 5M and the depth (height of the convex part) t of the concave parts 5M, a predetermined function (illumination area setting) is set in the diffractive optical element 5. Function, diffuse light generation function, and magnified illumination function). As a design method for optimizing the surface condition, a predetermined calculation method (simulation method) such as an iterative Fourier method is exemplified.

  Note that the diffractive optical element 5 is not limited to the one having the rectangular recess 5M, and may have a surface in which planes facing different directions are combined. For example, the diffractive optical element 5 may have a triangular recess having a slope as shown in FIG. Further, the diffractive optical element 5 may have a region having a rectangular recess 5M as shown in FIG. 3 and a region having a triangular recess as shown in FIG. . Then, by optimizing the surface conditions, the diffractive optical element 5 having a desired function can be formed.

  As shown in FIG. 1, the angle adjusting optical element 9 has an incident surface 9A on which laser light is incident and an exit surface 9B on which laser light from the incident surface 9A is emitted, and the laser light incident from the incident surface 9A. The injection angle is adjusted to be emitted from the emission surface 9B. In the present embodiment, the angle adjusting optical element 9 is disposed between the diffractive optical element 5 and the predetermined surface 11, and the incident surface 9 </ b> A of the angle adjusting optical element 9 is separated from the diffractive optical element 5. Laser light is incident. In the present embodiment, the angle adjusting optical element 9 is a refractive lens (field lens). The refractive lens includes an axial target lens that is rotationally symmetric with respect to the optical axis, such as a spherical lens or an aspherical lens. Alternatively, the angle adjusting optical element 9 may include a Fresnel lens or the like. The angle adjusting optical element 9 is capable of adjusting the emission angle of the laser light emitted from the emission surface 9B, and hence the incident angle of the laser light (irradiation light) with respect to the predetermined surface 11.

  As shown in FIGS. 1 and 2, in the present embodiment, the optical system 8 is arranged so that the optical axis of the optical system 8 does not intersect the predetermined surface 11. In other words, on the XY plane, the optical system 8 and the predetermined surface 11 are arranged in a predetermined positional relationship so that the optical axis of the optical system 8 and the predetermined surface 11 do not overlap.

  In the present embodiment, the optical axis of the optical system 8 and the Z-axis are substantially parallel, and the condensed and collimated laser light emitted from the optical system 8 travels along the optical axis. In the present embodiment, the predetermined surface 11 is provided at a position off the extension line of the laser light (laser light after being condensed and collimated) emitted from the optical system 8 and incident on the diffractive optical element 5. .

  Further, the diffractive optical element 5 is arranged so that the 0th-order light generated from the diffractive optical element 5 does not enter the predetermined surface 11. In other words, the incident surface 11 is provided at a position where zero-order light generated from the diffractive optical element 5 is not incident. The diffractive optical element 5 illuminates the predetermined surface 11 with the generated primary light via the angle adjusting optical element 9.

  As described above, the angle adjusting optical element 9 is provided between the diffractive optical element 5 and the predetermined surface 11. The angle adjusting optical element 9 is irradiated with the primary light from the diffractive optical element 5 and adjusts the emission angle of the emitted light. The angle adjusting optical element 9 can adjust the emission angle of light emitted from the diffractive optical element 5, and hence the incident angle of light with respect to the predetermined surface 11.

  Next, an example of the operation of the light source device 1 will be described. The laser light emitted from each of the plurality of laser light sources 2 enters the first optical element 6 of the optical system 8, passes through the first optical element 6, enters the second optical element 7, and the first optical element 6. 2 Passes through the optical element 7 and is emitted from the optical system 8. The optical system 8 collects and collimates a plurality of laser beams (light beam groups) incident on the diffractive optical element 5. The laser light emitted from the optical system 8 is incident on the incident surface 3 of the diffractive optical element 5, passes through the diffractive optical element 5, and is then emitted from the emergent surface 4 of the diffractive optical element 5. The diffractive optical element 5 generates diffracted light by the laser light incident from the incident surface 3 and emits it from the exit surface 4.

  Laser light (diffracted light, primary light) emitted from the exit surface 4 of the diffractive optical element 3 is incident on the incident surface 9A of the angle adjusting optical element 9 and passes through the angle adjusting optical element 9. The light is emitted from the exit surface 9B of the angle adjusting optical element 9. The angle adjusting optical element 9 adjusts the emission angle of the laser beam incident from the incident surface 9A and emits the light from the emission surface 9B. The laser beam emitted from the emission surface 9B of the angle adjusting optical element 9 is applied to the predetermined surface 11. Laser light that has passed through the optical system 8, the diffractive optical element 5, and the angle adjusting optical element 9 is incident on a predetermined area (for example, a rectangular area) of the predetermined surface 11 at a predetermined incident angle. As described above, the light source device 1 of the present embodiment illuminates the predetermined surface 11 with the predetermined illumination area (rectangular illumination area).

  As described above, according to the present embodiment, since a plurality of laser light sources 2 are provided, irradiation light having high illuminance (luminance) for illuminating the predetermined surface 11 can be generated, and the predetermined surface 11 can be improved. Can be illuminated. In addition, an optical system 8 that condenses a plurality of laser beams emitted from each of the plurality of laser light sources 2 on the center side of the predetermined surface 11 is provided, and the light condensed by the optical system 8 enters the diffractive optical element 5. Therefore, it is possible to generate irradiation light that can efficiently illuminate the predetermined surface 11. Then, by condensing a plurality of laser beams on the center side of the predetermined surface 11, high diffraction efficiency can be realized, and the light source device 1 with high light utilization efficiency can be realized.

  For example, as shown in FIG. 5, the optical system 8 is not provided, but a plurality of diffractive optical elements 5 are provided so as to correspond to the plurality of laser light sources 2, and the predetermined surface 11 is formed by light generated from each of the diffractive optical elements 5. Consider the case of illuminating in a superimposed manner. In FIG. 5, among the plurality of laser light sources 2, the diffractive optical element 5T corresponding to the laser light source 2T disposed at a position distant from the predetermined surface 11 causes the diffracted light (primary light) to be generated. In order to illuminate, it is necessary to increase the angle (diffraction angle) of the generated diffracted light. In other words, the diffractive optical element 5T needs to be designed so that the diffraction angle becomes large.

The ratio of the general, diffraction as the angle of the diffracted light generated from the optical element 5 (diffraction angle) is small, the diffraction efficiency (the light intensity emitted from the diffractive optical element 5 and the light intensity I _O that enters the diffractive optical element 5 I _P = I _P / I _O ) increases. Therefore, in the example shown in FIG. 5, the illuminance on the predetermined surface 11 of the diffracted light generated from the diffractive optical element 5T is smaller than the illuminance on the predetermined surface 11 of the diffracted light generated from the other diffractive optical elements 5. There is a possibility. In this case, the performance of the laser light source 2T cannot be fully exhibited, and the illumination efficiency is lowered.

  As described above, when a plurality of diffractive optical elements 5 are provided so as to correspond to each of the plurality of laser light sources 2 and the predetermined surface 11 is illuminated in a superimposed manner with the light generated from each of the diffractive optical elements 5, the predetermined surface 11 Depending on the positional relationship between the diffractive optical element 5 and the diffractive optical element 5, a situation occurs in which the diffraction angle of a certain diffractive optical element 5 (the diffractive optical element 5 T in FIG. 5) must be increased. The diffraction efficiency of the diffractive optical element 5 (5T) may be reduced.

  According to this embodiment, a plurality of laser beams emitted from each of the plurality of laser light sources 2 are condensed on the center side of the predetermined surface 11 by the optical system 8, and the collected light is incident on the diffractive optical element 5. Therefore, high diffraction efficiency can be realized. Therefore, by designing the light source device 1 and the diffractive optical element 5 so that the high diffraction efficiency of the diffractive optical element 5 can be obtained, a high illumination efficiency can be obtained using the light source device 1 including the diffractive optical element 5 having high diffraction efficiency. Thus, the predetermined surface 11 can be illuminated well.

  In the present embodiment, light for illuminating the predetermined surface 11 (diffracted light, primary light) with the highest diffraction efficiency within a range where the optical axis of the optical system 8 and the predetermined surface 11 do not intersect each other. ) Is adjusted (optimized) so that the diffractive optical element 5 can generate the optical system 8, the diffractive optical element 5, and the positional relationship between the diffractive optical element 5 and the predetermined surface 11. For example, the positional relationship between the optical system 8 and the diffractive optical element 5 and the predetermined surface 11 is adjusted so that the optical axis of the optical system 8 and the edge of the predetermined surface 11 (or the vicinity of the outside of the edge) intersect, In this positional relationship, the optical system 8 and the diffractive optical element 5 are adjusted so that the diffractive optical element 5 can generate light for illuminating the predetermined surface 11 with the highest diffraction efficiency.

  In the present embodiment, since the light source device 1 includes the plurality of laser light sources 2, generation of speckle patterns can be suppressed. The speckle pattern refers to a spotted pattern with high contrast generated in space when a scattering surface is irradiated with coherent light such as laser light and the scattered light is observed. Scattered light generated at each point on the scattering surface interferes with each other in a random phase relationship, resulting in a complicated interference pattern, which may illuminate the predetermined surface 11 with a non-uniform illumination distribution. In the present embodiment, the light source device 1 includes a plurality of laser light sources 2, and the laser beams emitted from each of the plurality of laser light sources 2 are incoherent with each other, and therefore have different illuminance distributions (luminance distributions). The predetermined surface 11 is illuminated with the light it has. Therefore, by irradiating the predetermined surface 11 with irradiation light based on these laser beams, the apparent speckle pattern can be reduced, and the illuminance distribution on the predetermined surface 11 can be made substantially uniform.

  In the present embodiment, the optical system 8 also has a collimating function (a collimating function, a collimating function) for collimating a plurality of laser beams (light beam groups) incident on the diffractive optical element 5. The diffractive optical element 5 on which the collimated laser light is incident can satisfactorily generate desired diffracted light with high diffraction efficiency. Further, the light incident on the incident surface 3 of the diffractive optical element 5 is collimated, and the wavefront of the light incident on the incident surface 3 of the diffractive optical element 5 is flattened to generate the desired diffracted light. The burden when designing the element 5 and the burden when manufacturing the light source device 1 can be reduced. The diffractive optical element 5 can generate desired diffracted light without parallelizing a plurality of laser beams (light beam groups) incident on the diffractive optical element 5, but in this case, diffractive optics for generating the desired diffracted light is used. There is a possibility that the design of the element 5 becomes complicated, the manufacture becomes complicated, and the manufacture of the light source device 1 becomes complicated. By collimating a plurality of laser beams (light beam groups) incident on the diffractive optical element 5, it is possible to reduce a burden when designing the diffractive optical element 5 and a burden when manufacturing the light source device 1.

  In the present embodiment, since the first optical element 6 and the second optical element 7 of the optical system 8 are refractive lenses, the burden on manufacturing can be reduced in designing the optical system 8.

  In the present embodiment, the diffractive optical element 5 is arranged so that the 0th-order light generated from the diffractive optical element 5 does not enter the predetermined surface 11. Thereby, even if zero-order light is generated from the diffractive optical element 5, it is possible to suppress the zero-order light from entering the predetermined surface 11. Therefore, the predetermined surface 11 can be illuminated in a desired state.

  In the present embodiment, the diffractive optical element 5 is designed so as not to generate zero-order light using a predetermined method such as the above-described iterative Fourier method, and is generated with a uniform illuminance distribution by the generated primary light. Although designed to illuminate the surface 11, for example, due to manufacturing errors (process errors) when manufacturing the diffractive optical element 5, wavelength errors of the laser light emitted from the laser light source 2, etc., diffractive optics There is a possibility that zero-order light is generated from the element 5. The error (blurring) in the wavelength of the laser light emitted from the laser light source 2 is caused by, for example, a temperature change. In many cases, the zero-order light is formed on an extension line of the laser light incident on the diffractive optical element 5. That is, in FIG. 1, the 0th-order light is often emitted in the normal direction (Z-axis direction) of the exit surface 4 of the diffractive optical element 5. In such a case, when the predetermined surface 11 is disposed on the extended line of the laser light incident on the diffractive optical element 5 (in the present embodiment, the position intersecting the optical axis of the optical system 8), the predetermined surface 11 In addition, zero-order light may be irradiated. When the predetermined surface 11 is irradiated with the 0th order light, the illuminance (luminance) of the portion of the predetermined surface 11 irradiated with the 0th order light may increase locally. In this case, the predetermined surface 11 cannot be illuminated with irradiation light having a uniform illuminance distribution. As will be described later, when the predetermined surface 11 is the incident surface of the spatial light modulation device of the projector, an image to be formed becomes defective due to local increase in illuminance (luminance) based on the 0th-order light. In the present embodiment, the predetermined surface 11 is disposed at a position off the extended line of the laser light incident on the diffractive optical element 5 from the optical system 8 (a position not intersecting with the optical axis of the optical system 8). Even if zero-order light is generated from the optical element 5, it is possible to suppress the zero-order light from being irradiated onto the predetermined surface 11. Therefore, the predetermined surface 11 can be illuminated with a uniform illuminance distribution.

  Further, in the XY plane, the light emitted from the optical system 8 is adjusted by adjusting the positional relationship between the optical system 8 and the predetermined surface 11 so that the optical axis of the optical system 8 and the predetermined surface 11 do not overlap. Direct supply to the predetermined surface 11 can be suppressed. For example, the diffractive optical element 5 may have moved from a predetermined position between the optical system 8 and the predetermined surface 11 for some reason, such as deterioration of a holding member that holds the diffractive optical element 5, or for some reason. There is a possibility that the diffractive optical element 5 may be damaged. In this case, if the positional relationship between the optical system 8 and the predetermined surface 11 is set so that the optical axis of the optical system 8 and the predetermined surface 11 intersect, the laser light emitted from the optical system 8 is directly Therefore, there is a possibility that a situation occurs in which the predetermined surface 11 is supplied. In this case, laser light that does not pass through the diffractive optical element 5 (not diffracted) enters the predetermined surface 11, which may damage the predetermined surface 11. In the present embodiment, the optical system 8 is arranged so that its optical axis does not intersect the predetermined surface 11, so that the occurrence of the above-described problems can be suppressed.

<Second Embodiment>
Next, a second embodiment will be described. In the following description, the same or equivalent components as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 6 is a schematic configuration diagram illustrating the light source device 1 according to the second embodiment. In the first embodiment described above, the optical system 8 is arranged so that its optical axis does not intersect the predetermined surface 11, but as shown in FIG. 6, the optical axis of the optical system 8 and the predetermined surface 11 are arranged. The positional relationship between the optical system 8 and the predetermined surface 11 may be set so that. The predetermined surface 11 may be disposed on an extension line of laser light (laser light after being condensed and collimated) that is emitted from the optical system 8 and incident on the diffractive optical element 5. If generation | occurrence | production of the malfunction described in the above-mentioned 1st Embodiment is fully suppressed, the compaction of the light source device 1 can be achieved by setting it as a structure as shown in FIG.

<Third Embodiment>
Next, a third embodiment will be described. FIG. 7 is a diagram showing an optical system 8 according to the third embodiment. In the above-described embodiment, the first optical element 6 of the optical system 8 is a plano-convex lens and the second optical element 7 is a plano-concave lens. However, as shown in FIG. The incident surface 6A may be a curved surface convex toward the −Z side (laser light source 2 side), and the emission surface 6B may be a plane substantially parallel to the XY plane. The optical system 8 shown in FIG. 7 also has a light collecting function and a collimating function.

<Fourth embodiment>
Next, a fourth embodiment will be described. FIG. 8 is a diagram showing an optical system 8 according to the fourth embodiment. In the above embodiment, the first optical element 6 and the second optical element 7 of the optical system 8 are refractive lenses. However, as shown in FIG. Each may be a Fresnel lens. In the present embodiment, the first optical element 6 is a plano-convex Fresnel lens, and the second optical element 7 is a plano-concave Fresnel lens. By using the Fresnel lens, the optical system 8 can be downsized. The optical system 8 shown in FIG. 8 also has a light collecting function and a collimating function.

  One of the first optical element 6 and the second optical element 7 may be a refractive lens, and the other may be a Fresnel lens. Further, at least one of the first optical element 6 and the second optical element 7 may be a diffractive optical element. That is, the optical system 8 can include at least one of a refractive lens, a Fresnel lens, and a diffractive optical element.

<Fifth Embodiment>
Next, a fifth embodiment will be described. FIG. 9 is a diagram showing an optical system 8 according to the fifth embodiment. As shown in FIG. 9, the optical system 8 may be composed of one refractive lens 6K. In the example shown in FIG. 9, the entrance surface of the refractive lens 6K constituting the optical system 8 is a curved surface convex toward the −Z side (laser light source 2 side), and the exit surface is substantially parallel to the XY plane. It is a plane. The optical system 8 shown in FIG. 9 has a light condensing function but does not have a collimating function.

  In the optical system 8 shown in FIG. 9, by adjusting the focal length of the refractive lens 6K, the positional relationship (distance) between the refractive lens 6K and the incident surface 3 of the diffractive optical element 5, a plurality of light incident on the diffractive optical element 5 is adjusted. Can be made substantially parallel to each other. For example, when the diameter of the laser beam incident on the incident surface of the refractive lens 6K is 9 mm and the focal length of the refractive lens 6K is 150 mm, the maximum is 1.7 with respect to the incident surface 3 of the diffractive optical element 5. The laser beam from the refractive lens 6K (optical system 8) can be incident at an incident angle of degrees. Thus, by using the refractive lens 6K having a long focal length, the wavefront of the light incident on the incident surface 3 of the diffractive optical element 5 can be brought into a nearly flat state.

<Sixth Embodiment>
Next, a sixth embodiment will be described. FIG. 10 is a diagram showing an optical system 8 according to the sixth embodiment. As shown in FIG. 10, the optical system 8 may be composed of one Fresnel lens 6F. The optical system 8 shown in FIG. 10 has a light condensing function but does not have a collimating function.

  Also in the present embodiment, the wavefront of light incident on the incident surface 3 of the diffractive optical element 5 is made almost flat by using the Fresnel lens 6F having a long focal length, as in the fifth embodiment. Can do.

<Seventh embodiment>
Next, a seventh embodiment will be described. FIG. 11 is a view showing a part of the light source device 1 according to the seventh embodiment, and FIG. 12 is an enlarged view showing the diffractive optical element 5 of FIG. In addition, in FIG. 11, illustration of the optical element 9 for angle adjustment is abbreviate | omitted.

  11 and 12, the diffractive optical element 5 has an incident part 3S and an emission part 4S, and diffracts the light incident on the incident part 3S by the emission part 4S. In the present embodiment, a collimating optical element 6 </ b> C that parallelizes a plurality of laser beams (light beam groups) supplied to the emitting unit 4 </ b> S is disposed in the incident unit 3 </ b> S of the diffractive optical element 5. The collimating optical element 6C disposed in the incident portion 3S includes a Fresnel lens. In addition, a surface relief hologram element 5H is disposed in the emission portion 4S. The diffractive optical element 5 is incident on the incident part 3S by the surface relief hologram element 5H arranged in the emission part 4S, and diffracts the laser light supplied from the incident part 3S to the emission part 4S.

  As shown in FIG. 11, the optical system 8 of the present embodiment has one refractive lens 6K and has a condensing function, but does not have a collimating function. In the present embodiment, even when the optical system 8 has only a light collecting function, the surface relief disposed in the exit portion 4S by the collimating optical element 6C disposed in the entrance portion 3S of the diffractive optical element 5 is used. A plurality of laser beams (light beam groups) incident on the mold hologram element 5H can be made parallel.

  In this embodiment, desired diffracted light can be satisfactorily generated with high diffraction efficiency while suppressing an increase in the number of parts.

<Eighth Embodiment>
Next, an eighth embodiment will be described. FIG. 13 is a diagram showing a diffractive optical element 5 according to the eighth embodiment. A characteristic part of the present embodiment is that the diffractive optical element 5 receives a light from the optical system 8 and emits light to be supplied to the predetermined surface 11 with a predetermined diffraction efficiency (diffraction angle). The cell region 5S is provided. Each of the cell regions 5S can generate diffracted light. 13A and 13B, the laser beam condensed and collimated by the optical system 8 is incident on the incident surface of the diffractive optical element 5 shown in FIG. 13A and FIG. 13B. The optical system 8 collectively illuminates the plurality of cell regions 5S of the diffractive optical element 5 with laser light. The cell region 5S is a square region having one side of, for example, about 1 mm on the XY plane parallel to the incident surface (exit surface) of the diffractive optical element 5.

  In FIG. 13A, the diffractive optical element 5 is adjusted (designed) so that a plurality of irradiation regions formed by light supplied to the predetermined surface 11 from each of the cell regions 5S coincide on the predetermined surface 11. Has been. That is, in the example shown in FIG. 13A, the diffractive optical element 5 illuminates a predetermined region of the predetermined surface 11 with laser light generated from each of the plurality of cell regions 5S.

  In the example shown in FIG. 13A, the light source device 1 can illuminate the predetermined region of the predetermined surface 11 with light generated from each cell region 5S so that the predetermined surface 11 is efficiently illuminated with high illuminance. it can. Moreover, generation | occurrence | production of a speckle pattern can be suppressed and the predetermined surface 11 can be illuminated with substantially uniform illumination distribution.

  In FIG. 13B, the diffractive optical element 5 is adjusted (designed) so that the diffraction efficiencies of the cell regions 5S are substantially equal. That is, in the example shown in FIG. 13B, the angles (diffraction angles) of the diffracted light generated from each of the cell regions 5S are substantially equal. Thereby, each cell region 5S can generate diffracted light with high diffraction efficiency, and can efficiently illuminate the predetermined surface 11 with high illuminance. Moreover, generation | occurrence | production of a speckle pattern can be suppressed.

  In the example shown in FIG. 13B, some of the diffracted light generated from some cell regions 5S out of the plurality of cell regions 5S may leak outside the predetermined surface 11. Since 5S generates diffracted light having high diffraction efficiency and high luminance, the predetermined surface 11 can be illuminated with high illuminance. Then, by overlapping the diffracted light generated from each cell region 5S on the predetermined surface 11, the predetermined surface 11 can be illuminated with a substantially uniform illuminance distribution.

  In the first to eighth embodiments described above, the light source device 1 has a plurality of laser light sources 2 arranged in a two-dimensional direction (XY direction), but is arrayed in a one-dimensional direction (for example, the X-axis direction). You may provide the laser light source 2 arrange | positioned in the shape.

  In the first to eighth embodiments described above, among the transmission type diffractive optical elements (diffraction gratings), the phase modulation type diffractive optical element is used as the diffractive optical element, but the amplitude modulation type diffractive optical element is used. An element can also be used. Further, the invention is not limited to the transmission type diffractive optical element, and a reflection type diffractive optical element can also be used. Further, for example, a transmissive diffractive optical element and a reflective diffractive optical element may be combined. Then, by optimizing the surface conditions of these diffractive optical elements, the diffractive optical elements can have a desired function.

<Ninth Embodiment>
Next, a ninth embodiment will be described. In the present embodiment, an example of an image display device to which the light source device 1 described in each of the above embodiments is applied will be described.

  FIG. 14 is a schematic configuration diagram illustrating an image display device including the light source device 1 (1R, 1G, 1B) described in each of the above-described embodiments. In the present embodiment, a projection type image display device (projector) that projects color light including image information generated by a spatial light modulator on a screen via a projection system will be described as an example of the image display device.

  In FIG. 14, the projection type image display device PJ includes a projection unit U that projects light including image information on a screen 100 (display surface). An image is formed on the screen 100 by projecting light from the projection unit U onto the screen 100. The projection type image display device PJ of the present embodiment uses the screen 100 as a transmission screen and projects light including image information onto the screen 100 from the front side of the screen 100.

  The projection unit U includes a first light source device 1R that can illuminate the predetermined surface 11 with the first basic color light (red light), and a second light source device that can illuminate the predetermined surface 11 with the second basic color light (green light). 1G, a third light source device 1B that can illuminate the predetermined surface 11 with the third basic color light (blue light), and an incident surface (predetermined surface) 11 that is illuminated by the first light source device 1R. It has a first spatial light modulator 10R that modulates light according to image information and an incident surface (predetermined surface) 11 that is illuminated by the second light source device 1G, and illuminates the illuminated light according to image information. A third spatial light modulator 10G having a second spatial light modulator 10G to be modulated and an incident surface (predetermined surface) 11 illuminated by the third light source device 1B, and which modulates the illuminated light in accordance with image information. 10B and the basic color light modulated by the spatial light modulators 10R, 10G, and 10B are combined. Synthesis system 20, the light generated by the color synthesizing system 20 and a projection system 21 for projecting on the screen 100. Each of the spatial light modulation devices 10R, 10G, and 10B includes a liquid crystal device. In the following description, the spatial light modulator is appropriately referred to as a light valve.

  The light valve includes an incident-side polarizing plate, a panel having a liquid crystal sealed between a pair of glass substrates, and an emission-side polarizing plate. A pixel electrode and an alignment film are provided on the glass substrate. The light valve constituting the spatial light modulator transmits only light in a predetermined vibration direction, and the basic color light incident on the light valve is light-modulated by passing through the light valve.

  The plurality of laser light sources 2 of the first light source device 1R each emit red (R) laser light. The first light source device 1R illuminates the incident surface 11 of the first light valve 10R based on the red laser light.

  The plurality of laser light sources 2 of the second light source device 1G each emit green (G) laser light. The second light source device 1G illuminates the incident surface 11 of the second light valve 10G based on the green laser light.

  The plurality of laser light sources 2 of the third light source device 1B each emit blue (B) laser light. The third light source device 1G illuminates the incident surface 11 of the third light valve 10B based on the blue laser light.

  Each basic color light (modulated light) modulated by passing through each light valve 10R, 10G, 10B is synthesized by the color synthesis system 20. The color synthesis system 20 is configured by a dichroic prism, and the red light (R), the green light (G), and the blue light (B) are synthesized by the color synthesis system 20 to become full-color synthesized light. Full-color synthesized light emitted from the color synthesis system 20 is supplied to the projection system 21. The projection system 21 projects full-color synthesized light on the screen 100. The projection system 21 is a so-called enlargement system that enlarges an image on the incident side and projects it on the screen 100.

  The projection unit U projects full-color composite light including image information via the light valves 10R, 10G, and 10B illuminated by the light source devices 1R, 1G, and 1B onto the screen 100 using the projection system 21. As a result, a full-color image is formed on the screen 100. The viewer appreciates the image projected on the screen 100 by the projection unit U.

  The light valves 10R, 10G, and 10B of the projector PJ of the present embodiment are illuminated with irradiation light having high illuminance and uniform illuminance distribution by the light source devices 1R, 1B, and 1G having high illumination efficiency. . Therefore, the projector PJ can display a good image with high contrast.

  In the description using FIG. 14, the front projection type projector that projects light including image information onto the screen 100 from the front side of the screen 100 has been described as an example. However, the projection unit U, the screen 100, The projection unit U is disposed on the back side of the screen 100, and the so-called rear projector that projects light including image information onto the screen 100 from the back side of the screen 100. The device 1 can also be applied.

  In each of the above-described embodiments, a transmissive liquid crystal device (light valve) is used as the spatial light modulator, but a reflective liquid crystal device can also be used, for example, a DMD (Digital Micromirror Device) or the like. A reflective light modulator (mirror modulator) may be used.

  In addition, the projector PJ of the above-described embodiment includes the first, second, and third light source devices 1R, 1G, and 1B each having the laser light source 2 that can emit each basic color light (R, G, and B). A light source device having a configuration in which a red laser light source emitting red light (R), a green laser light source emitting green light (G), and a blue laser light source emitting blue light (B) are arranged in an array The structure which has one may be sufficient. In this case, the laser light emission operation of the laser light source capable of emitting each basic color light is performed in a time-sharing manner, and one light source is controlled by controlling the operation of the light valve in synchronization with the laser light emission operation of each laser light source. A full color image can be displayed on the screen 100 with the device and one light valve.

  In the projector of the above-described embodiment, the light source device 1 illuminates the spatial light modulation device, and the image is displayed on the screen 100 by light passing through the spatial light modulation device. ) May not have a spatial light modulator. For example, the light source device 1 of each embodiment described above is applied to a so-called slide projector that illuminates the surface of a slide (positive film) containing image information with the light source device 1 and projects light containing image information on a screen. It is also possible.

  The image display device may be a direct-view image display device that does not have a projection system and directly observes the image of the spatial light modulation device.

<Tenth Embodiment>
Next, a tenth embodiment will be described. In the present embodiment, an example of an illumination device to which the light source device 1 described in each of the above embodiments is applied will be described.

  FIG. 15 is a schematic configuration diagram illustrating the illumination device 200 according to the present embodiment. As illustrated in FIG. 15, the lighting device 200 includes the light source device 1 described in each of the above embodiments. According to the illuminating device 200 configured as described above, the illuminating device 200 itself includes the light source device 1 that can obtain a desired light amount and has a long life, and thus the illuminating device 200 itself has low power consumption and a long life. It will be the one that was made.

<Eleventh embodiment>
Next, an eleventh embodiment will be described. In the present embodiment, an example of a monitor device to which the light source device 1 described in each of the above embodiments is applied will be described.

  FIG. 16 is a schematic configuration diagram showing a monitor device 400 according to the present embodiment. In FIG. 16, the monitor device 400 includes a device main body 410 and an optical transmission unit 420. The apparatus main body 410 includes the light source device 1 described in the above embodiments.

  The light transmission unit 420 includes two light guides 421 and 422 on the light sending side and the light receiving side. Each of the light guides 421 and 422 is a bundle of a large number of optical fibers, and can send laser light to a distant place. The light source device 1 is disposed on the incident side of the light guide 421 that transmits light, and the diffusion plate 423 is disposed on the emission side thereof. The laser light emitted from the light source device 1 travels through the light guide 421, is sent to the diffusion plate 423 provided at the tip of the light transmission unit 420, is diffused by the diffusion plate 423, and irradiates the subject.

  An imaging lens 424 is also provided at the tip of the light transmission unit 420, and reflected light from the subject can be received by the imaging lens 424. The received reflected light travels through the light guide 422 on the receiving side and is sent to a camera 411 as an imaging means provided in the apparatus main body 410. As a result, the camera 411 can capture an image based on the reflected light obtained by irradiating the subject with the laser light emitted from the light source device 1.

  According to the monitor device 400 configured as described above, the light source device 1 can irradiate the subject, so that the brightness of the captured image obtained by the camera 411 can be increased.

  Note that the light source device 1 described in each of the above embodiments can also be used as a light source of a laser processing machine.

It is a schematic block diagram which shows the light source device which concerns on 1st Embodiment. It is a schematic perspective view which shows the light source device which concerns on 1st Embodiment. It is a schematic diagram for demonstrating an example of the diffractive optical element which concerns on 1st Embodiment. It is a schematic diagram for demonstrating an example of the diffractive optical element which concerns on 1st Embodiment. It is a figure which shows the light source device as a comparative example. It is a schematic block diagram which shows the light source device which concerns on 2nd Embodiment. It is a figure which shows the optical system which concerns on 3rd Embodiment. It is a figure which shows the optical system which concerns on 4th Embodiment. It is a figure which shows the optical system which concerns on 5th Embodiment. It is a figure which shows the optical system which concerns on 6th Embodiment. It is a figure which shows a part of light source device which concerns on 7th Embodiment. It is the figure which expanded the diffractive optical element which concerns on 7th Embodiment. It is a schematic diagram for demonstrating an example of the diffractive optical element which concerns on 8th Embodiment. It is a figure which shows the image display apparatus which concerns on 9th Embodiment. It is a figure which shows the illumination which concerns on 10th Embodiment. It is a figure which shows the monitor apparatus which concerns on 11th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light source device, 2 ... Laser light source, 3S ... Incident part, 4S ... Ejection part, 5 ... Diffractive optical element, 5S ... Cell area | region, 6 ... 1st optical element, 6C ... Collimating optical element, 7 ... 2nd optical element DESCRIPTION OF SYMBOLS 8 ... Optical system, 9 ... Optical element for angle adjustment, 10 ... Predetermined member (spatial light modulation device), 11 ... Predetermined surface (incident surface), 100 ... Screen (display surface), PJ ... Image display device (projector) , 200 ... lighting device, 400 ... monitor device

Claims (14)

A light source device that generates irradiation light for irradiating a predetermined surface,
A plurality of laser light sources for emitting laser light;
A diffractive optical element that diffracts incident light and emits light to be supplied to the predetermined surface;
An optical system that receives a plurality of laser beams emitted from each of the laser light sources, collects the incident laser beams, and causes the collected light to enter the diffractive optical element; Prepared,
The optical system is characterized in that at least a part of the plurality of laser beams is condensed on the center side of the predetermined surface, and the light is incident on the diffractive optical element.   The light source device according to claim 1, wherein the optical system collimates the plurality of laser beams incident on the diffractive optical element. The diffractive optical element has an incident part and an emission part, diffracts the light incident on the incident part by the emission part,
The light source device according to claim 1, further comprising: a collimating optical element that is arranged in the incident portion and collimates the plurality of laser beams supplied to the emission portion.   The light source device according to any one of claims 1 to 3, wherein the optical system is arranged so that an optical axis of the optical system does not intersect a predetermined region of the predetermined surface.   5. The diffractive optical element is disposed so that zero-order light generated from the diffractive optical element does not enter a predetermined region of the predetermined surface. 6. Light source device.   The light source apparatus according to claim 1, wherein the optical system includes a refractive lens.   The light source apparatus according to claim 1, wherein the optical system includes a Fresnel lens. The diffractive optical element has a plurality of cell regions that receive light from the optical system and emit light to be supplied to the predetermined surface with predetermined diffraction efficiency,
The light source device according to claim 1, wherein diffraction efficiency of each cell region is substantially equal. The diffractive optical element includes a plurality of cell regions that receive light from the optical system and emit light to be supplied to the predetermined surface with predetermined diffraction efficiency,
The light source device according to claim 1, wherein a plurality of irradiation regions formed by light supplied to the predetermined surface from each of the cell regions are coincident with each other on the predetermined surface. .   An image display device, wherein the light emitted from the light source device according to any one of claims 1 to 9 is irradiated, and an image is displayed by light passing through the predetermined surface.   The image display device according to claim 10, wherein the predetermined surface includes an incident surface of a spatial light modulator that modulates the irradiated light according to an image signal.   12. A projector comprising the image display device according to claim 10 or 11, further comprising a projection system that projects light including image information via the predetermined surface onto a display surface.   An illumination device comprising the light source device according to any one of claims 1 to 9.   A monitor device comprising the light source device according to claim 1.

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